On: PHP Pitfalls

[fyolnish]

You don’t even need serverside debuggers or fancy instrumentation to achieve this. The function microtime() returns a timestamp in microseconds. This makes it easy for you to check the passage of time at key points during your application’s execution path.

Yes, that's just as good as a real profiler.

[Udo → fyolnish]

Obviously I'm not saying that, but it's a reasonably good method of determining how certain parts of your code perform.